Yeah Legolas uses his "long knife" at the Hornburg, but (as others have said) only as a backup because he's out of arrows. And even then I've always seen it more as a short-sword, but I guess we're getting into Balrog wings territory to argue over it.
I don't recall Aragorn receiving a knife. Was that in the movies?
In any event, I tend to rely more on general depictions of cultures, rather than taking single characters as being representative. E.g., Mirkwood elves are described as being able to hit a bird's eye in the dark with their bows. For high elves I was recalling hosts of elves with bright spears from the first age, and in general many textual references to spears, but then again Legolas tells the company that they breathe so loudly the elves of Lorien could shoot them in the dark. So there's that.
Or Dwarves and swords: somebody up thread said that it's hard to imagine Gimli using a sword, but at the end of the Hobbit all of Dain's folk come equipped with mattocks and a shortsword.
Correct, Aragorn was gifted a dagger by Celeborn in the movies. In the books he received only the Elfstone and a sheath for Anduril. I was only commenting that perhaps that was one source of the poster's belief that Elves were somehow associated with daggers.
If we are going to assume Elves continued to have their same preferred weaponry from the First Age (which is logical and my own preference as well), then Tolkien was fairly specific in his stating that the Noldor preferred swords and shields, the Vanyar spears, and the Teleri (who would later in part become the Sindar, Nandor, and Silvan of Middle-earth) the bow.
But again, Middle-earth is not as simple and archetypal as something like Dungeons and Dragons or other generic fantasy. These were complex cultures that lived for thousands of years. It's not as if individuals didn't use all different weapons as might have been their preference; Gil-Galad is the most obvious example as he was about as Noldo as one can be but used a spear.
That said, if we want to talk about the broad cultural preferences of the Elves of Middle-earth, which by the late Third Age was almost entirely Silvan and Noldor, then Tolkien is clear in stating them to be bows and swords, for the two groups respectfully.